KNOWN VARIANTS:
DC-8 Series 10: Initial production model; 2 built
DC-8 Series 20: Similar to Series 10 but with more powerful engines for operation in hot or high-altitude conditions; 49 built
DC-8 Series 30: Long-range model and first designed for intercontinental operations; 52 built
DC-8 Series 40: Similar to Series 30 but equipped with more powerful Rolls-Royce engines; 29 built
DC-8 Series 50: Improved model with more powerful engines and revised cabin layout allowing 10 additional passengers to be seated, also featured new wing leading edge that reduced drag improving speed and range; 162 built
DC-8AF Jet Traders: Freighter model of Series 50
DC-8CF Jet Traders: Convertible cargo/passenger model of Series 50
DC-8 Super 60: Generic designation for three new models described below, all three available in passenger only (DC-8-6_), cargo only (DC-8-6_F), or combination cargo/passenger (DC-8-6_CF) variants; 262 built
DC-8 Super 61: Enlarged model with extended fuselage for up to 259 passengers
DC-8 Super 62: Long-range model with lengthened fuselage for greater fuel capacity but still carrying 189 passengers, also featured larger wingspan
DC-8 Super 63: Final production model combining enlarged fuselage of the Super 61 with new wing and other aerodynamic improvements of the Super 62
DC-8 Super 71: Super 61 airframes equipped with new more fuel efficient GE/SNECMA turbofans allowing much improved range and meeting noise regulations
DC-8 Super 72: Super 62 airframes equipped with new engines
DC-8 Super 73: Super 63 airframes equipped with new engines
EC-24 Former United Airlines DC-8-54F modified to simulate enemy communications and control systems and used by the US Navy; 1 converted